Wirelessly posted (Mozilla/5.0 (iPhone; U; CPU iPhone OS 4_2_1 like Mac OS X; en-us) AppleWebKit/533.17.9 (KHTML, like Gecko) Version/5.0.2 Mobile/8C148 Safari/6533.18.5)
The sim is what gives you a remote chance of tracking the person, if it's pulled, that's gone.
WiFi would work, as long as the person didn't restore. If the person did, no location data or services would be set up, you would have absolutely no way of tracking him.
I know man, it really sucks. My little bro had his jacked right out of his hands and I tried everything in my power. I made a police report and tried to use find my iPhone and everything. If the thief restores it and takes out the sim, it's basically an entirely new iPhone.
The only thing you can do is if you lost it in a store or school, have them dig into the video logs and try to find out who it was.